The present invention relates to manually powered vehicles. More particularly, the present invention relates to a manually powered drive mechanism and a vehicle and method of operating a vehicle employing same.
Unicycles, bicycles and tricycles have been used for years to provide an economic mode of transportation, for fun and entertainment, etc. Bicycles are by far the most common of these devices and generally employ power from a person""s lower body, wherein foot pedals typically connect to crank shafts, which in turn rotate a sprocket that drives a chain linking a rear wheel. The drive mechanism of a standard bicycle is relatively simple, which has no doubt helped the bicycle to achieve such enormous popularity.
One primary use of the bicycle is to provide exercise. Bicycles provide an excellent workout for the lower body. Bicycles, however, do not equally use a person""s upper body muscles. On a bicycle, the rider typically uses the rider""s upper body to steer and to prop-up or support their upper body. Consequently, bicycles do not provide a good total body workout.
One type of machine that does provide a total body workout is a rowing machine. Rowing machines simulate the motion one uses to row a boat. Rowing machines typically consist of a frame that is supported on the floor. Rowing machines provide a seat that rides on a rail between a forward position and a rear position. Rowing machines typically provide handles that easily push forward but provide a resistance to being pulled back. Although rowing machines provide excellent exercise for many muscles including legs, arms, back, shoulders and stomach, they are purely for the benefit of exercise and do not have the ability to move people.
Manually powered vehicles have been developed that combine arm and leg power. These machines attempt to harness the overall total body benefits of a rowing type exercise with a device that can move people. While these machines exist, they have to date not gained widespread commercial popularity. There appear to be a number of reasons to account for the fact that xe2x80x9crowbikesxe2x80x9d and the like have not become popular. First, many of the existing rowbikes appear to be awkward and fragile. Second, the mechanisms that drive the rowbikes appear to be complicated. That is, when compared to a bicycle, the rowbike designs contain many more parts, which are awkwardly configured. The numerous and intricately juxtaposed parts create cost and add to the potential for mechanical failure.
Accordingly, there exists a need for a simple, inexpensive, total body workout device that is also capable of transporting a rider.
The present invention provides a driving mechanism for a manually powered vehicle. More particularly, the present invention provides a manually powered driving mechanism that is suitable for driving vehicles having two, three or four wheels. The driving mechanism includes a frame. At least one rear wheel rotatably connects to the frame via a drive shaft.
A first free-wheel driver, for example, a free-wheel drive sprocket connects to the drive shaft, which holds the rear wheel. A lever arm pivotally attaches to the middle portion of the frame. One end of the lever arm includes a handle that can be grasped and pulled by a rider. The other end of the lever arm rotatably connects to a second free-wheel driver or drive sprocket. The first and second free-wheel drive sprockets spin freely in one direction but not the other.
A linkage or linked chain wraps around a portion of the second free-wheel wheel sprocket and extends towards the rear wheel and wraps around a portion of the first free-wheel drive sprocket. The first free-wheel drive sprocket drives the rear wheel. The chain runs from the first free-wheel drive sprocket, over a roller that pivotally attaches to the frame and back to the second free-wheel drive sprocket, which connects to the end of the lever arm.
When the rider pulls the lever arm towards the rider""s body, the second free-wheel drive sprocket grabs the chain and pulls the chain forward over the roller. The chain in turn pulls the first free-wheel drive sprocket, which rotates the rear wheel forward. When the rider pushes the lever arm away from the rider""s body, the second free-wheel drive sprocket spins freely to allow the lever arm to return to the pull position without moving the linked chain or the vehicle.
In one embodiment, the roller is positioned on the frame between the first and second free-wheel sprockets. A second roller mounts to the frame closer to the front of the vehicle than the first roller. The linkage or chain extends over the first roller, then downwardly away from the frame and around the bottom of the second free-wheel sprocket (connected to the lever arm), and then back up towards the frame and around the second roller.
From the second roller, the chain extends towards the front of the vehicle and then downwardly from the frame around a tensioner, which is pivotally attached to the frame. A spring or other type of biasing mechanism, such as a piston/cylinder, is biased to rotate the tensioner towards the frame in one rotational direction, while the chain, when pulled by the lever arm and second free-wheel driver, tends to pull the tensioner towards the frame in the opposite rotational direction. The net result is that the tensioner remains extended generally perpendicularly downwardly from the frame and operates to hold the linkage or chain away from the lever arm and the second free-wheel sprocket, to allow same to move back and forth and drive the vehicle without being obstructed by the chain, which runs towards the back of the vehicle to the rear wheel.
The vehicle includes a seat that slidingly engages the frame. The seat slides backward and forward, respectively, as the person or rider pulls the lever arm back towards the rider""s body and pushes the lever arm forward towards the front of the vehicle. The lever arm includes a brake lever for manually operating a cable driven brake. The brake includes a brake pad attached adjacent to one of the wheels. In an embodiment, the brake pad frictionally engages a front, steerable wheel.
In one embodiment, at least one front, steerable wheel rotatably attaches to the frame. A steering column extends from the front, steerable wheel, through the frame, and connects to a steering bar that has foot pads attached on each end. Each foot pad holds one of the rider""s feet, so that the rider steers the vehicle with the rider""s legs. The rider extends his or her right leg to turn the steering bar counterclockwise from the rider""s viewpoint to turn the vehicle to the left. The rider extends his or her left leg to turn the steering bar clockwise from the rider""s viewpoint to turn the vehicle to the right.
The driving mechanism in one embodiment includes a multitude of different gears. The first or rear free-wheel driver includes a number of different gear settings, for example, a number of different free-wheel sprockets of different size. A standard gear shift rear derailer mounts at the rear of the vehicle and moves the linked chain from one gear to another when the rider engages and moves a gear shift lever and a link between the gear shift lever and the derailer.
The driving mechanism in one preferred embodiment drives one rear wheel. For proper steering of the vehicle it is preferred that the driving mechanism not drive two rear wheels. In any case, the driving mechanism of the present invention is easily adapted to power two, three or four-wheeled vehicles. The four-wheeled embodiment may also be configured as a wheelchair. The driving mechanism does not change, rather, the wheels mount differently and the steering and braking mechanisms are modified.
Accordingly, it is an advantage of the present invention to provide a total body workout driving mechanism and a moveable vehicle embodying same.
It is another advantage of the present invention to provide a rowing vehicle having a simplistic driving mechanism.
It is a further advantage of the present invention to provide a rowing vehicle having a cost effective driving mechanism.
It is still another advantage of the present invention to provide a driving mechanism for a two-wheeled rowing vehicle.
It is still a further advantage of the present invention to provide a driving mechanism for a three-wheeled rowing vehicle.
It is yet another advantage of the present invention to provide a driving mechanism for a four-wheeled rowing vehicle.
Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Invention and the figures.